Field
The present invention relates to a light emitting device which includes at least one light emitting element.
Description of Related Art
Due to the small size and good power efficiency, semiconductor light emitting elements such as LEDs and LDs have been used for various light sources, and research on efficient extracting of light from the light emitting elements has been progressing. In order to obtain a desired directivity to the emitting light, there have been light emitting devices proposed which are provided with a sealing member to serve as a lens integrally formed therein. In those light emitting devices, further studies have been progressing on improving the light extraction efficiency and on the shape of the lens.
In a light emitting device with an integrally formed lens, the closer the relative sizes of the light emitting element and the sealing member serving as a lens becomes, the more amount of light which is emitted from the light emitting element is reflected at an larger angle than the critical angle of total reflection on the inner surface of the sealing member, resulting in a decrease in the amount of light extracted to outside.
On the other hand, with the size of the light emitting element remaining unchanged, the larger the size of the supporting base member on which the light emitting element is mounted with respect to the sealing member, the more amount of light which is emitted from the light emitting element is reflected at the sealing member absorbed by the upper surface of the supporting base member, resulting in a reduction of light extraction efficiency.
For this reason, in order to reduce the ratio of light totally reflecting at the inner surface of the sealing member, and to reduce light absorbed by the upper surface of the supporting base member, a light emitting device which includes a sealing member having a size sufficiently greater than that of the supporting base member has been proposed (see JP 2007-273764A and JP 2009-88235 A).
However, in the light emitting device which includes a sealing member having a size sufficiently greater than that of the supporting base member, external impact tends to act on the extension portion of the sealing member which is extended outward from the supporting base member, which is highly likely to cause detachment at the interface between the sealing member and the supporting base member.
The occurrence of such detachment may result in a decrease in the light extraction efficiency and/or in the life of the product, which may further deteriorate quality and/or reliability of the product.